Semiconductor processing apparatus and method

ABSTRACT

A semiconductor processing apparatus is provided. The apparatus includes a body portion, which includes at least one semiconductor processing unit. Each semiconductor processing unit includes a recess formed on an upper surface of the body portion, wherein a bottom surface of the recess has at least one location and a peripheral. The bottom surface ascends from the at least one location toward the peripheral against a direction of gravity or descends from the at least one location toward the peripheral following the direction of gravity. Each semiconductor processing unit also includes a first channel that connects to the recess at the at least one location, as well as at least one second channel connecting to the recess at the peripheral. Each of the first channel and the at least one second channel serves as an inlet or an outlet via which a fluid enters or exits the recess. A method according to the present disclosure may control a flowing direction of a fluid flowing across a substrate surface. When the fluid flow as programmed, the fluid may contact the substrate surface and process the surface via various physical and/or chemical reactions.

TECHNICAL FIELD

The present disclosure generally relates to semiconductor technologyand, more particularly, to a semiconductor processing apparatus and amethod thereof.

BACKGROUND

A surface of a semiconductor wafer substrate (referred to as a“substrate surface” hereinafter) is very sensitive to micro contaminantsthat are on the surface. In order to obtain a qualified substratesurface, it is required to remove the micro contaminants from thesurface and subsequently to prevent the micro contaminants fromreattaching to the surface after being removed. This requires thesubstrate surface to go through several rounds of cleaning steps inorder to remove any metallic ions, atoms, organic substances andmicroparticles that may be on the substrate surface. Existing substratesurface cleaning techniques fall into two major categories: wet cleaningand dry cleaning, with the former being the mainstream techniques. Wetcleaning techniques involve washing a substrate surface using a mixtureof a liquid acid or base solution and deionized water, followed byrinsing and drying procedures. Regarding substrate surface cleaning usedin industrial production, a semiconductor wafer may be processed orotherwise treated by being immersed in various processing fluids insequence. Alternatively, each of the processing fluids may be sprayedonto a semiconductor wafer that is spinning. Either way, the processingfluids may cause various physical and/or chemical reactions with thesubstrate surface of the semiconductor wafer, thereby producing asubstrate surface that meets processing requirements. Wet cleaning anddry cleaning alike demand a rather large amount of ultrapure chemicalsolutions and/or gases, which become wasted fluids that are to bedisposed after processing. The large amount of ultrapure chemicalsolutions and/or gases consumed contribute to a high cost of thecleaning process, and the post-processing expenses of the wasted fluidsraise the cost even higher, not to mention disadvantageous environmentalimpacts the wasted fluids may cause.

Methods and new techniques have been sought after by semiconductormanufacturing engineers to reduce consumption of chemicals for thecleaning process, which would reduce the processing cost as well as thepost-processing expenses of the wasted fluids. A reduction in theconsumption of chemicals would also make the cleaning process safer andless harmful to the environment. Chinese patent application CN103367197Adiscloses a substrate surface processing system that is able toeffectively reduce the amount of chemicals or fluids consumed by a wetcleaning process for a semiconductor substrate surface, and also able toperform in-situ recycling and post-processing of the used fluids.Specifically, the substrate surface processing system includes aprocessing unit having a micro chamber for a semiconductor siliconwafer. The micro chamber includes an upper chamber portion and a lowerchamber portion, similar to those shown in FIG. 1. When the upperchamber portion and the lower chamber portion are in a closed position,they form the micro chamber that is closed. The semiconductor wafer,namely, a substrate, maybe placed inside the closed micro chamber, andprocessing to either an upper or a lower surface of the substrate may beperformed by sending a processing fluid (liquid or gas) into the microchamber. It is apparent that a flowing pattern of the processing fluidflowing inside the micro chamber, a length of period the processingfluid staying inside the micro chamber, and how the processing fluidcontacts the upper or lower surface of the substrate will all directlyaffect the result of the surface processing. As the processing fluid mayflow on the upper or lower surface of the substrate in a random fashion,the result of the surface processing may not be highly repeatable.Therefore, in order to achieve repeatable result for the surfaceprocessing, a method and/or a design is necessary that enables accuratecontrol of the flowing of the processing fluid inside the micro chamber.

SUMMARY

A purpose of the present disclosure is to provide a semiconductorprocessing apparatus and method, via which an accurate control of aflowing direction of a processing fluid may be achieved, therebycontrolling a process and a result of the processing fluid processing asubstrate surface.

Specifically, the present disclosure discloses the following:

A semiconductor processing apparatus has a body portion that includes atleast one semiconductor processing unit. Each of the at least onesemiconductor processing unit may include a recess formed on an uppersurface of the body portion. A bottom surface of the recess may have atleast one location and a peripheral. The bottom surface ascends from theat least one location toward the peripheral against a direction ofgravity or descends from the at least one location toward the peripheralfollowing the direction of gravity. Each of the at least onesemiconductor processing unit may also include a first channelconnecting to the recess at the at least one location. Each of the atleast one semiconductor processing unit may also include at least onesecond channel connecting to the recess at the peripheral. Each of thefirst channel and the at least one second channel serves as an inlet oran outlet via which a fluid enters or exits the recess.

Preferably, the at least one location is located at a center of thebottom surface.

Preferably, the at least one semiconductor processing unit comprises onesemiconductor processing unit, and the bottom surface comprises a slopedsurface ascending from the at least one location toward the peripheralagainst the direction of gravity.

Preferably, the at least one semiconductor processing unit comprises onesemiconductor processing unit, and the bottom surface comprises a slopedsurface descending from the at least one location toward the peripheralfollowing the direction of gravity.

Preferably, a guiding trench is disposed at the peripheral of the bottomsurface, and the guiding trench is connected to the at least one secondchannel.

Preferably, the at least one second channel comprises a plurality ofsecond channel, and the plurality of second channels are distributed ina circle surrounding the center of the bottom surface of the recess.

Preferably, the body portion also includes a groove disposed on an outerside of the at least one semiconductor processing unit, the groovecapable of collecting the fluid overflowing from the recess. Preferably,the body portion further includes a third channel connecting the grooveand an external environment, the third channel capable of sending outthe fluid collected by the groove.

Preferably, the at least one semiconductor processing unit comprises onesemiconductor processing unit, and the bottom surface ascends from theat least one location toward the peripheral against the direction ofgravity. Moreover, the bottom surface comprises a cross sectionalprofile described by a curve. The curve has a slope varying from alarger value to a smaller value as the bottom surface ascends.

Preferably, the at least one semiconductor processing unit comprises onesemiconductor processing unit, and the bottom surface descends from theat least one location toward the peripheral following the direction ofgravity. Moreover, the bottom surface comprises a cross sectionalprofile described by a curve. The curve has a slope varying from asmaller value to a larger value as the bottom surface descends.

Preferably, the curve is represented by a function y=−C/x, wherein C isa constant greater than 0, wherein the center is an origin of thefunction, and wherein a direction extending from the center toward theperipheral is a positive direction of a variable x of the function.

Preferably, the curve is represented by a function y=A·In(x)+C, whereineach of A and C is a constant, wherein the center is an origin of thefunction, and wherein a direction extending from the center toward theperipheral is a positive direction of a variable x of the function.

Preferably, the semiconductor processing apparatus also includes a coverportion disposed on top of the body portion. The cover portion includesa fourth channel, wherein a chamber is formed between the recess of thebody portion and a lower surface of the cover portion, and wherein thefourth channel connects the chamber to an external environment.

Preferably, the body portion further includes a first engagementfeature, and the cover portion further has a second engagement featurethat corresponds to the first engagement feature. When the body portionand the cover portion are engaged with one another, the body portion andthe cover portion are tightly connected together and seal one another.

Preferably, at least one fluid guiding trench is formed on the lowersurface of the cover portion, and is connected to the fourth channel.

Preferably, the at least one semiconductor processing unit comprises aplurality of semiconductor processing units, and each of thesemiconductor processing units is capable of processing a respective oneregion of a surface of a substrate.

A semiconductor processing method may include the following steps: (1)Place a substrate on top of a recess of a body portion, with a lowersurface of the substrate facing downward for processing. The bodyportion has a first channel and a second channel. Each of the firstchannel and the second channel connects to the recess at a respectiveopening which is at a respectively different height. (2) Send a fluid tothe recess via at least one of the first channel and the second channel,such that the fluid fills up a space between the lower surface of thesubstrate and the recess and contacts the lower surface of thesubstrate. (3) Drain the fluid that is inside the recess via one of thefirst channel and the second channel that has the respective openinglocated at a lower location.

Preferably, the draining of the fluid inside the recess comprisescontrolling a moving speed and a moving direction of a solid-liquid-gasboundary. The solid-liquid-gas boundary is formed between the fluid andthe lower surface of the substrate. This would control an amount and aphysical distribution of a residue of the fluid that is left at thelower surface of the substrate after the draining.

Preferably, when the moving speed of the solid-liquid-gas boundarysatisfies a first predetermined condition, the fluid leavessubstantially no residue on the lower surface of the substrate as thesolid-liquid-gas boundary moves across the lower surface of thesubstrate.

Preferably, when the moving speed of the solid-liquid-gas boundarysatisfies a second predetermined condition, the fluid forms a thin filmof a predetermined thickness on the lower surface of the substrate asthe solid-liquid-gas boundary moves across the lower surface of thesubstrate.

Preferably, a bottom surface of the recess descends from a center of thebottom surface toward a peripheral of the bottom surface following adirection of gravity. The first channel has the respective opening at ahigher location, and the second channel has the respective opening at alower location.

Preferably, during the draining of the fluid inside the recess, thesolid-liquid-gas boundary moves from the center of the bottom surfacetoward the peripheral of the bottom surface.

Preferably, a bottom surface of the recess ascends from a center of thebottom surface toward a peripheral of the bottom surface against adirection of gravity. The first channel has the respective opening at alower location, and the second channel has the respective opening at ahigher location.

Preferably, during the draining of the fluid inside the recess, thesolid-liquid-gas boundary moves from the peripheral of the bottomsurface toward the center of the bottom surface.

A semiconductor surface inspection method may include the followingsteps: (1) Place a substrate on top of a body portion such that each ofa plurality of semiconductor processing units abuts a lower surface ofthe substrate. (2) Send a fluid to at least one unit of the plurality ofsemiconductor processing units via either a first channel or a secondchannel of the at least one unit. The fluid contacts the lower surfaceof the substrate and removes or dissolves a contaminant at the lowersurface of the substrate. (3) Drain the fluid via either one of thefirst channel and the second channel. (4) Respectively collect andinspect the fluid drained from the at least one unit to obtain adistribution of the contaminant in different regions of the substrate.

Preferably, a bottom surface of a recess of each of the plurality ofsemiconductor processing units ascends from a center of the bottomsurface toward a peripheral of the bottom surface against a direction ofgravity. The first channel has a respective opening at a lower location,and the second channel has a respective opening at a higher location. Asthe fluid flows in the recess, the contaminant removed or dissolved inthe fluid moves from the center to the peripheral.

Preferably, the fluid is drained via the first channel, and thecontaminant removed or dissolved in the fluid is drained out of therecess along with the fluid, and is subsequently collected forinspection.

Preferably, the fluid is drained via the second channel, and thecontaminant removed or dissolved in the fluid is drained out of therecess along with the fluid, and is subsequently collected forinspection.

Preferably, a bottom surface of a recess of each of the plurality ofsemiconductor processing units descends from a center of the bottomsurface toward a peripheral of the bottom surface following a directionof gravity. The first channel has a respective opening at a higherlocation, and the second channel has a respective opening at a lowerlocation.

Preferably, the fluid is drained via the first channel, and thecontaminant removed or dissolved in the fluid is drained out of therecess along with the fluid, and is subsequently collected forinspection.

Preferably, the fluid is drained via the second channel, and thecontaminant removed or dissolved in the fluid is drained out of therecess along with the fluid, and is subsequently collected forinspection.

The apparatuses and methods revealed in the present disclosure mayexhibit at least the following advantages and benefits: Through choosinga kind of a fluid, a location of an inlet and an outlet via which thefluid is sent into and out of a recess, an internal structure of therecess, as well as a pressure of the fluid, one may control a flowingdirection and a flowing speed of the fluid such that the fluid may flowin the recess according to a plan and contact with a surface of asubstrate. The fluid may thus process or otherwise treat the surface ofthe substrate via various physical and/or chemical reactions. That is,through a careful and detailed design of the recess, with an aid ofgravity, one may accurately control the flowing direction and speed ofthe fluid as the fluid flow inside the recess. This would in turncontrol the physical and/or chemical reactions, and thus a result ofprocessing the surface of the substrate at various locations of thesurface. For example, some specific design of a structure or profile ofthe recess may enable the fluid to flow in the recess and contact thesurface of the substrate with a constant linear speed, which may give auniform processing result of the surface.

BRIEF DESCRIPTION OF THE DRAWINGS

The drawings are intended to assist in understanding the presentdisclosure as described below but not to limit a scope of the presentdisclosure in any way. Shape, size and scale of each physical part ofthe drawings are for illustrative purposes only, meant to assist inunderstanding the present disclosure but not to specifically limit ordefine a shape, size or scale of any physical part according to thepresent disclosure. One having ordinary skills in the art may realizevarious embodiments according to the present disclosure using any shape,size and scale of the parts that are suitable for a specific applicationor situation.

FIG. 1 illustrates a micro chamber processing apparatus.

FIG. 2 is a sectional view of a semiconductor processing apparatusaccording to an embodiment of the present disclosure.

FIG. 2A illustrates a zoom-in view of circle I of FIG. 2.

FIG. 2B illustrates a zoom-in view of circle II of FIG. 2.

FIG. 3 is a top view of a body portion of a semiconductor processingapparatus according to an embodiment of the present disclosure.

FIG. 4 is a sectional view of a body portion of a semiconductorprocessing apparatus according to an embodiment of the presentdisclosure.

FIG. 4A illustrates a zoom-in view of circle I of FIG. 4.

FIG. 4B illustrates a zoom-in view of circle II of FIG. 4.

FIG. 5 is a bottom view of a cover portion of a semiconductor processingapparatus according to an embodiment of the present disclosure.

FIG. 6 is a sectional view along sectional line A-A of FIG. 5.

FIG. 7 is a sectional view of a semiconductor processing apparatusaccording to another embodiment of the present disclosure.

FIG. 7A illustrates a zoom-in view of circle I of FIG. 7.

FIG. 8 is a sectional view of a body portion of a semiconductorprocessing apparatus according to another embodiment of the presentdisclosure.

FIG. 8A illustrates a zoom-in view of circle I of FIG. 8.

FIG. 9 is a bottom view of a cover portion of a semiconductor processingapparatus according to another embodiment of the present disclosure.

FIG. 9A is a sectional view along sectional line A-A of FIG. 9.

FIG. 10 illustrates structural features of the recess of a semiconductorprocessing apparatus according to another embodiment of the presentdisclosure.

FIG. 11 is a sectional view of a semiconductor processing apparatusaccording to another embodiment of the present disclosure.

FIG. 11A illustrates a zoom-in view of circle I of FIG. 11.

FIG. 11B is a sectional view along sectional line A-A of FIG. 11.

FIG. 11C illustrates a zoom-in view of circle I of FIG. 11B according toan embodiment of the present disclosure.

FIG. 11D illustrates a zoom-in view of circle I of FIG. 11B according toanother embodiment of the present disclosure.

The numeral references labeled in the drawings are as follows:

1 is a body portion; 11 is a semiconductor processing unit; 111 is arecess; 1111 is a location; 1112 is a peripheral; 112 is a firstchannel; 113 is a second channel; 114 is a guiding trench; 12 is a firstgroove; 13 is a third channel; 14 is a first engagement feature; 2 is acover portion; 21 is a fourth channel; 22 is a second engagementfeature; 23 is a fluid guiding trench; 24 is a second groove; 25 is afifth channel; 3 is a fluid; 4 is a substrate.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

To make the above objects, features and advantages of the presentdisclosure more obvious and easier to understand, the present disclosureis further described in detail below using various embodiments asdescribed below. The embodiments are intended to explain various aspectsof the present disclosure as described below but not to be understood inany way as limiting realizations of the present disclosure. Based on thepresent disclosure, one having ordinary skills in the art may constructvarious alternative embodiments, which should be deemed within the scopeof the present disclosure.

FIG. 2 is a sectional view of a semiconductor processing apparatusaccording to an embodiment of the present disclosure, whereas FIG. 7 isa sectional view of a semiconductor processing apparatus according toanother embodiment of the present disclosure. As shown in each of FIG. 2and FIG. 7, the semiconductor processing apparatus may include a bodyportion 1 and a cover portion 2. At least one semiconductor processingunit 11 may be formed on body portion 1, and each of the at least onesemiconductor processing unit 11 may have a recess 111 that is formed onan upper surface of body portion 1. A bottom surface of recess 111 mayinclude at least one location 1111. In some embodiments, the bottomsurface may descend from location 1111 toward peripheral 1112 of thebottom surface following a direction of gravity. In some embodiments,the bottom surface may ascend from location 1111 toward peripheral 1112of the bottom surface against the direction of gravity. A first channel112 that connects to recess 111 may be formed on body portion 1 atlocation 1111, and a second channel 113 that connects to recess 111 maybe formed on body portion 1 at location 1112. First channel 112 and/orsecond channel 113 may be used as an inlet and/or outlet for a fluid 3.

According to an aspect of the present disclosure, a flowing directionand a flowing speed of fluid 3 over a surface of a substrate 4 may becontrolled. Specifically, the flowing direction and the flowing speedmay be controlled by one or more of the following parameters: a type orkind of fluid 3, a location of each of the inlet and the outlet whichallows fluid 3 to enter or exit recess 111, an internal structure ofrecess 111, and a pressure of fluid 3. Through controlling the flowingdirection and the flowing speed of fluid 3, fluid 3 may flow throughrecess 111 in a predetermined manner while making contact with thesurface of substrate 4 and having various physical and/or chemicalreactions with the surface, thereby processing or otherwise treating thesurface of substrate 4. Moreover, recess 111 may be carefully designedsuch that the flowing direction and/or the flowing speed of fluid 3, asdriven by gravity and flowing in recess 111, may be accuratelycontrolled. Consequently, the physical and/or chemical reactions thatfluid 3 has at various locations of the surface of substrate 4 may becontrolled, resulting in a desired treatment of the surface. Forexample, the structure of recess 111 may be specifically designed suchthat fluid 3 may move at a predetermined constant linear velocity as itflows through recess 111 and makes contact with various locations of thesurface of substrate 4, thereby producing a uniform treatment result.

FIG. 2A illustrates a zoom-in view of circle I of FIG. 2, and FIG. 2Billustrates a zoom-in view of circle II of FIG. 2. As shown in FIGS. 2,2A and 2B, the semiconductor processing apparatus may include bodyportion 1, and body portion 1 may include semiconductor processing unit11, a first groove 12, a third channel 13, and a first engagementfeature 14. Semiconductor processing unit 11 may include recess 111 thatis formed on the upper surface of body 1, first channel 112 thatconnects to an internal area of recess 111, second channel 113 thatconnects to a peripheral area of recess 111. Recess 111 may includelocation 1111 that is located on the bottom surface of recess 111 wherefirst channel 112 connects to recess 111, as well as location 1112 wheresecond channel 113 connects to recess 111. The bottom surface may ascendfrom location 1111 toward peripheral 1112 against the direction ofgravity. Fluid 3 may simultaneously enter or exit recess 111 via bothfirst channel 112 and second channel 113. Alternatively, fluid 3 mayenter/exit recess 111 via first channel 112 and exit/enter recess 111via second channel 113, respectively.

FIG. 3 is a top view of a body portion of a semiconductor processingapparatus according to an embodiment of the present disclosure, and FIG.4 is a sectional view of a body portion of a semiconductor processingapparatus according to an embodiment of the present disclosure. Inaddition, FIG. 4A illustrates a zoom-in view of circle I of FIG. 4,whereas FIG. 4B illustrates a zoom-in view of circle II of FIG. 4. Asshown in FIG. 3, body portion 1 may be designed to have an arbitraryshape according a need, and may have a certain thickness which allowsthe formation of recess 111 therein. In an embodiment, body portion 1may be in a shape of a rectangular parallelepiped, whereas the uppersurface of body portion 1 may be a square. The semiconductor processingapparatus of FIG. 3 may have a recess 111 formed on an upper surface ofbody portion 1, and recess 111 may be used to accommodate a substrate 4.Recess 111 may have a shape of a cylinder, and may be symmetrical withrespect to a center. As shown in FIG. 4, location 1111 of the bottomsurface of recess 111 may be located at the center of a bottom surfaceof recess 111. The bottom surface may be a curved surface that ascendsfrom location 1111 toward peripheral 1112 of the bottom surface againstthe direction of gravity. In each of various embodiments, the curvedsurface may have a slope of a respectively different value as itascends, or a slope of a varying value. In some embodiments wherein thecurved surface has a constant slope as it ascends from location 1111toward peripheral 1112, recess 111 is embodied as a conical surfacehaving an apex pointing downward, as shown in FIG. 4 and FIG. 4A. Afirst channel 112 may be formed in body portion 1 at location 1111 andconnect to recess 111, and a second channel 113 may be formed in bodyportion 1 at peripheral 1112 and connect to recess 111. That is, firstchannel 112 may connect to recess 111 at location 1111 which is at thecenter of the bottom surface of recess 111, and second channel 113 mayconnect to recess 111 at location 1112 which is at the peripheral of thebottom surface of recess 111. Second channel 113 may connect to one ormore guiding trenches 114; guiding trench 114 may be located atperipheral 1112 of the bottom surface of recess 111 and surroundlocation 1111. As fluid 3 flows to or otherwise reach peripherallocation 1112 of the bottom surface of recess 111, fluid 3 may entersecond channel 113 via guiding trench 113. Thanks to guiding trench 113,fluid 3 may flow evenly in radial directions and enter second channel113. Fluid 3 may simultaneously enter or exit recess 111 via both firstchannel 112 and second channel 113. Alternatively, fluid 3 mayenter/exit recess 111 via first channel 112 and exit/enter recess 111via second channel 113, respectively.

As shown in FIGS. 3, 4 and 4B, in some embodiments, body portion 1 mayalso include a first groove 12 and a first engagement feature 14. Firstgroove 12 may be disposed on an outer side of semiconductor processingunit 11, capable of collecting fluid 3 that overflows from recess 111.First groove may be of a circular shape as disposed on the upper surfaceof body portion 1. Body portion 1 may further include a third channel 13that is connected to first groove 12. Third channel 13 may be capable ofsending or otherwise drain the fluid 3 collected in the first groove 12to the outside. Monitoring a flow rate of each of first channel 112,second channel 113 and third channel 13, one may judge whether or notthe semiconductor processing apparatus is malfunctioning. Firstengagement feature 14 may engage with a corresponding feature of thecover portion, thereby sealing the internal chamber from the externalenvironment.

For the immediate embodiment, operation of the semiconductor processingapparatus may be described as follows: Substrate 4 may be placed in alevel position on top of recess 111 of body portion 1, with a surface ofsubstrate 4 facing downward toward recess 111 and waiting to beprocessed. A spacing may thus be formed between the lower surface ofsubstrate 4 and the bottom surface of recess 111. The spacing maydecrease in height from central location 1111 toward peripheral location1112. Fluid 3 may be sent into recess 111 via first channel 112 of bodyportion 1. As fluid 3 continues being sent into recess 111, fluid 3 maygradually fill up the spacing, starting from central location 1111 andin a direction against the direction of gravity. When the spacingbetween substrate 4 and body portion 1 is filled by fluid 3, fluid 3 maycompletely cover the lower surface of substrate 4, i.e., the surface ofsubstrate that needs to be processed. In some embodiments, fluid 3 maycontinue entering recess 111 via first channel 112, and exit recess 111via second channel 113. Alternatively, fluid 3 may overflow from recess111 and into first groove 12, and then flow to the external via thirdchannel 13. At any desired time, fluid 3 may be stopped from furtherentering recess 111, such that fluid 3 that is already inside thespacing between the lower surface of substrate 4 and recess 111 may stayin the spacing for a predetermined period of processing time, duringwhich fluid 3 may continue having physical and/or chemical reactionswith the lower surface of substrate 4. At any desired time, analternative fluid of another kind may be sent into recess 111 to replacefluid 3 that currently fills the spacing between recess 111 andsubstrate 4. The process may be repeated using various fluids havingsame and/or different compositions, until a desired treatment result forthe lower surface of substrate 4 is obtained. Fluid inside recess 111may exit via both first channel and second channel. An entering speedand an exit speed of fluid 3 as it enters and exits recess 111,respectively, may be controlled by adjusting a pressure setting and/or avacuum setting of gas-liquid pumps.

In the immediate embodiment, a shape of the curved surface of recess 111may be carefully designed to achieve the desired treatment result. Thatis, location 1111 may be located at the center of the bottom surface ofrecess 111, and the bottom surface may be a curved surface ascendingfrom location 1111 toward peripheral 1112 of the bottom surface ofrecess 111 against the direction of gravity. A curvature or slope of thecurved surface may be determined or otherwise defined as part of adesign of body portion 1. In the process of fluid 3 flowing from thecenter of recess 111 toward peripheral 1112 of recess 111, each of aflowing direction of fluid 3, a flowing speed of fluid 3, and a pressureexerted on the lower surface of substrate 4 by fluid 3 may varydepending on the specific shape of the curved surface, which maysubsequently affect the result of the processing of the lower surface ofsubstrate 4 due to the physical and/or chemical reactions.

With a similar principle, the semiconductor processing apparatus mayalternatively send fluid 3 into recess 111 via second channel 113 whichconnects to peripheral 1112 of recess 111. That is, fluid 3 mayinitially emerge at peripheral 1112 of recess 111, and then flow towardcentral location 1111 along the bottom surface of recess 111 due togravity given that the bottom surface of recess 111 is sloped, ascendingfrom central location 1111 of the bottom surface toward peripheral 1112of the bottom surface in a direction against the direction of gravity.During this process, fluid 3 may contact the lower surface of substrate4 and process or otherwise treat the lower surface of substrate 4. Afterfluid 3 fills up the spacing between the lower surface of substrate 4and recess 111, fluid 3 may start to flow out of body portion 1 viafirst channel 112, at which moment fluid 3 may, in some embodiments,maintain substrate 4 in a floating state and floating on fluid 3. Insome other embodiments, substrate 4 may continue abutting body portion1. Starting from this moment, fluid 3 may continue exiting via firstchannel 112 while entering via second channel 113. Since recess 111 issloped toward the center of recess 111, a flowing direction of fluid 3may be well controlled after fluid 3 enters recess 111 via secondchannel 113. That is, fluid 3 may flow toward the center of recess 111because of gravity. Due to a constant slope of the bottom surface ofrecess 111 as the bottom surface descends from peripheral 1112 of recess111 toward the center of recess 111, fluid 3 may flow from peripheral1112 toward the center of recess 111 at a same flowing speed in allradial directions. Therefore, during the flowing, fluid 3 may contactthe lower surface of substrate 4 uniformly in all radial directions.Given that substrate 4 typically has a circular surface, fluid 3 maythus treat the lower surface of substrate 4 uniformly in all radialdirections of substrate 4 during the flowing. Namely, various locationsof substrate 4 that share a same radial distance may be equally treatedor processed by fluid 3. After a desired treatment to the lower surfaceof substrate 4 is achieved, fluid 3 may be stopped from entering recess111 via second channel 113, and fluid 3 that is already in recess 111may flow toward the center of recess 111 and drain via first channel112. During the draining of fluid 3, a solid-liquid-gas boundary betweenfluid 3 and substrate 4 may firstly emerge at peripheral 1112 of thebottom surface of recess 111. As fluid 3 continues to exit via firstchannel 112, the solid-liquid-gas boundary between fluid 3 and substrate4 may move from a peripheral of substrate 4 toward a center of substrate4, and continue to move in this direction until fluid 3 is completelyseparated from substrate 4. In the end, all fluid 3 may completely exitrecess 111 via first channel 112. Note that a contact area between fluid3 and substrate 4, particularly the solid-liquid-gas boundary, iscompletely controlled during the whole process of draining fluid 3. Thesolid-liquid-gas boundary may firstly emerge at peripheral 1112 ofsubstrate 4 as a circle. The solid-liquid-gas boundary, whilemaintaining its circular shape, may gradually move from the peripheralof substrate 4 toward the center of substrate 4, and finally disappearat the center of substrate 4.

FIG. 5 shows a bottom view of a cover portion 2 of a semiconductorprocessing apparatus according to an embodiment of the presentdisclosure, and FIG. 6 is a sectional view along sectional line A-A ofFIG. 5. As shown in FIGS. 5 and 6, the semiconductor processingapparatus may include a cover portion 2 disposed above body portion 1.Cover portion 2 may have a fourth channel 21, a fluid guiding trench 23,a fifth channel 25 and a second engagement feature 22. When body portion1 and cover portion 2 are disposed in a closed position, a closedchamber is formed between recess 111 of body portion 1 (which is locatedon the upper surface of body portion 1) and a lower surface of coverportion 2. The closed chamber may communicate with an externalenvironment via fourth channel 21. Substrate 4 may be positioned withrespect to recess 111 of body portion 1 via cover portion 2. Each ofbody portion 1 and cover portion 2 may be made of ultrapure and/orcorrosion-resistant materials such as polytetrafluoroethylene, quartz,silicon carbide or PPT plastic, capable of handling poisonous and/orcorrosive fluid 3 with safety, cleanliness and stability.

In some embodiments, fourth channel 21 may be located at a centrallocation of cover portion 2. A second groove 24 (which may be of acircular shape) and fifth channel 25 that connects to second groove 24may be located outside of a contact area between cover portion 2 andsubstrate 4. When body portion 1 and cover portion 2 are disposed in theclosed position, second groove 24 of cover portion 2 may be connectedwith first groove 12 of body portion 1. Fluid may enter and/or exit theclosed chamber via fourth channel 21 and fifth channel 25 such thatfluid 3 may be introduced to, or drained from, an upper surface and/or aside surface of substrate 4, thereby adjusting a pressure, maintaining apressure and/or creating a vacuum therein.

As shown in FIGS. 4 and 5, first engagement feature 14 of body portion 1may correspond to second engagement feature 22 of cover portion 2. Whenbody portion 1 and cover portion 2 are engaged with one another, bodyportion 1 and cover portion 2 may seal one another and form a closedmicro chamber that is sealed from the outside environment. Firstengagement feature 14 may be located at the peripheral of the uppersurface of body portion 1, and may be an indented edge having a circularshape. Second engagement feature 22 may be located at the peripheral ofthe lower surface of cover portion 2, and may be an extruding edgehaving a circular shape. When body portion 1 and cover portion 2 aredisposed in the closed position, the indented edge of body portion 1 mayengage the extruding edge of cover portion 2, thereby ensuring thesealing between body portion 1 and cover portion 2. Apparently, in someother embodiments, first engagement feature 14 may be an extruding edgehaving a circular shape, whereas second engagement feature 22 may be anindented edge having a circular shape.

As shown in FIG. 5, at least one fluid guiding groove 23 may be providedon the lower surface of cover portion 2, and the at least one fluidguiding groove 23 is connected to fourth channel 21. In someembodiments, the at least one fluid guiding groove 23 may include twoguiding grooves that cross one another in an “X” shape. In someembodiments, the at least one fluid guiding groove 23 may include evenmore guiding grooves that cross each other. Fluid guiding grooves 23 maycross each other at one location or at multiple locations. When fluidguiding grooves 23 cross at one location, the one location may belocated at a location where fourth channel 21 is located. In addition,fluid guiding grooves 23 may connect to fourth channel 21 at the onelocation. Fluid guiding grooves 23 may form a structure that has acenter of symmetry. Consequently, when fluid flows via fourth channel 21to increase or decrease a pressure of the micro chamber formed betweenbody portion 1 and cover portion 2, a change of pressure may beuniformly exerted onto substrate 4. This is because the symmetry of thestructure formed by fluid guiding grooves 23 may ensure a uniformity ofthe fluid flowing in fluid guiding grooves 23. Specifically, whenvacuuming via fluid guiding grooves 23, air pressure within fluidguiding grooves 23 is reduced, creating a pressure difference betweenthe upper surface and the lower surface of substrate 4, which isdisposed below fluid guiding grooves 23. The pressure difference mayforce substrate 4 to move upward and abut fluid guiding grooves 23,thereby forming a closed space. As the vacuuming continues, substrate 4is eventually attached to cover portion 2.

In an embodiment, a semiconductor processing unit 11 may include arecess 111 formed on an upper surface of a body portion 1. Recess 111may be largely a rectangle, and may have a plurality of locations 1111on a bottom surface of recess 111. The plurality of locations 1111 mayform a straight line, and the bottom surface may ascend, 111 against adirection of gravity, from the straight line toward both of left andright sides of recess. Specifically, the straight line formed by theplurality of locations 1111 may be a line of symmetry of the bottomsurface of recess 111, and the bottom surface of recess 111 may includeslopes each ascending from the line of symmetry toward either of theleft side and right side of recess 111. A shape of recess 111 may besymmetrical with respect to a vertical surface encompassing the line ofsymmetry. Namely, the bottom surface of recess 111 may have a V-shapedcross section. Furthermore, a plurality of first channels 112 may eachconnect to a lowest point of the bottom surface of recess 111 to theoutside environment. The plurality of first channels 112 may be arrangedalong the line of symmetry such that fluid 3 may enter recess 111uniformly along the line of symmetry located on the bottom surface ofrecess 111. A plurality of second channels 113 may include two rows ofchannels, each row arranged along a direction of the line of symmetry,each row also connecting either the left side or the right side ofrecess 111 with the external environment. The semiconductor processingunit of the immediate embodiment may be used to treat or otherwiseprocess a silicon wafer having a rectangular shape. Specifically, fluid3 may enter recess 111 via the plurality of second channels 113 that aresymmetrically arranged on the left side and the right side of recess111. Due to gravity, fluid 3 may flow uniformly from the left side andthe right side of recess 111 toward a lowest location of recess 111.During the flowing, fluid 3 may contact a lower surface of the siliconwafer, thereby processing or treating the lower surface of the siliconwafer. Since fluid 3 flows uniformly from both sides of recess 111toward the lowest location of recess 111, equally uniform is theprocessing or treatment to both sides of the lower surface of thesilicon wafer. It is obvious that in some other embodiments, the bottomsurface of recess 111 may descend from the line of symmetry toward bothleft and right sides of recess 111. Namely, the bottom surface of recess111 may have an inverse-V-shaped cross section. The plurality of firstchannels 112 may each connect a highest point of the bottom surface ofrecess 111 to the outside environment. The plurality of second channels113 may include two rows of channels, each row connecting either theleft side or the right side of recess 111 and the external environment.Each of the left side and the right side of recess 111 represents alowest location of recess 111. A silicon wafer having a rectangularshape may be processed or treated by a semiconductor processing unit ofthe immediate embodiment.

FIG. 7 is a sectional view of a semiconductor processing apparatusaccording to another embodiment of the present disclosure, and FIG. 7Aillustrates a zoom-in view of circle I of FIG. 7. FIG. 8 is a sectionalview of a body portion of a semiconductor processing apparatus accordingto another embodiment of the present disclosure, and FIG. 8A illustratesa zoom-in view of circle I of FIG. 8. As shown in FIGS. 7 and 7A, thesemiconductor processing apparatus capable of processing a substrate 4may include a body portion 1, and body portion 1 may include asemiconductor processing unit 11. Semiconductor processing unit 11 mayinclude a recess 111 that is formed on body 1 and capable ofaccommodating substrate 4. Recess 111 may include a location 1111 thatis located on a bottom surface of recess 111. The bottom surface maydescend from location 1111 toward a peripheral 1112 of the bottomsurface of recess 111 following the direction of gravity. At location1111, body portion 1 may have a first channel 112 that connects recess111 to an external environment. At peripheral 1112, body portion 1 mayfurther have a second channel 113 that connects recess 111 to theexternal environment. Fluid 3 may enter or exit recess 111 via either orboth of first channel 112 and second channel 113.

Specifically, as shown in FIGS. 8 and 8A, body portion 1 may be in ashape of a rectangular parallelepiped, whereas the upper surface of bodyportion 1 may be a square. Recess 111 may be formed on an upper surfaceof body portion 1, capable of accommodating substrate 4. Location 1111may be located at a center of the bottom surface of recess 111. Thebottom surface may be a sloped surface descending from location 1111toward peripheral 1112. In some alternative embodiments, the bottomsurface may be a curved surface having a descending trend that may ormay not vary as the curved surface descends from location 1111 towardperipheral 1112. Recess 111 may be symmetrical around the center of thebottom surface. In some embodiments wherein the curved surface has aconstant slope as it descends from location 1111 toward peripheral 1112,the bottom surface of recess 111 is embodied as a conical surface havingan apex pointing upward. First channel 112 may be formed in body portion1 at location 1111 and may connect recess 111 to the externalenvironment, and second channel 113 may be formed in body portion 1 atperipheral 1112 and may connect recess 111 to the external environment.That is, first channel 112 may connect to the center of the bottomsurface of recess 111, and fluid 3 may enter recess 111 via firstchannel 112. In some embodiments, a plurality of second channels 113 maybe formed, which are distributed circularly surrounding the center ofthe bottom surface of recess 111. Fluid 3 may exit recess 111 via theplurality of second channels 113.

FIG. 9 shows a bottom view of a cover portion 2 of a semiconductorprocessing apparatus according to an embodiment of the presentdisclosure, and FIG. 9A is a sectional view along sectional line A-A ofFIG. 9. As shown in FIGS. 9 and 9A, cover portion 2 may have a fourthchannel 21 formed therein. When body portion 1 and cover portion 2 aredisposed in a closed position, a closed chamber is formed between recess111 of body portion 1 (which is formed on the upper surface of bodyportion 1) and a lower surface of cover portion 2. The closed chambermay communicate with the external of the closed chamber via fourthchannel 21. A second groove 24 (which may be of a circular shape) and afifth channel 25 that connects second groove 24 to the externalenvironment may be formed on the bottom surface of cover portion 2. Whenbody portion 1 and cover portion 2 are disposed in a closed position,second groove 24 may be connected with first groove 12 of body portion1. Cover portion 2 may include a second engagement feature 22 that maycorrespond to first engagement feature 14 of body portion 1. When bodyportion 1 and cover portion 2 are engaged with one another, body portion1 and cover portion 2 may be tightly connected together and seal oneanother.

For the immediate embodiment, operation of the semiconductor processingapparatus may be described as follows: Substrate 4 may be placed in alevel position on top of recess 111 of body portion 1. A spacing maythus be formed between the lower surface of substrate 4 and recess 111.The spacing may increase in height from the center of substrate 4 to theperipheral of substrate 4. Fluid 3 may be sent into recess 111 via firstchannel 112 that connects to the center of recess 111. Initially, fluid3 may emerge at central location 1111 of recess 111. Since the bottomsurface of recess 111 is a sloped surface descending, following thedirection of gravity, from central location 1111 of recess 111 towardperipheral 1112 of recess 111, fluid 3 may flow along the bottom surfaceof recess 111 from central location 1111 toward peripheral 1112 due togravity. During the flowing, fluid 3 may contact the lower surface ofsubstrate 4 and process or treat the lower surface of substrate 4 viavarious chemical and physical reactions caused by fluid 3 at the lowersurface of substrate 4. After fluid 3 fills up the spacing betweensubstrate 4 and recess 111, fluid 3 may exit recess 111 via secondchannel 113 of body portion 1. Substrate 4 may either maintain in afloating state under the effect of fluid 3 or abut against body portion1. Starting from this moment, fluid 3 may continue exiting recess 111via second channel 113 while entering recess 111 via first channel 112.Since the bottom surface of recess 111 is sloped, a flowing direction offluid 3 may be well controlled after fluid 3 enters recess 111 via firstchannel 112. That is, fluid 3 may flow toward peripheral 1112 of thebottom surface of recess 111 because of gravity. Fluid 3 may flow with asame flowing speed in all radial directions of recess 111, and thuscontact the lower surface of substrate 4 uniformly in all radialdirections during the flowing. Given that substrate 4 typically has acircular surface, fluid 3 may thus treat the lower surface of substrate4 uniformly in all radial directions of substrate 4 during the flowing.Namely, various locations of the lower surface of substrate 4 that sharea same radial distance from the center of recess 111 may be equallytreated or processed by fluid 3. After a desired treatment result to thelower surface of substrate 4 is achieved, fluid 3 may be stopped fromentering recess 111 via first channel 112, and fluid 3 that is alreadyin recess 111 may flow toward peripheral 1112 of recess 111. Asolid-liquid-gas boundary between fluid 3 and substrate 4 may firstlyemerge at the center of the bottom surface of recess 111. As fluid 3continues to exit via second channel 113, the solid-liquid-gas boundarybetween fluid 3 and substrate 4 may move from a center of substrate 4toward a peripheral of substrate 4, and continue to move in thisdirection until fluid 3 is completely separated from substrate 4. In theend, all fluid 3 may completely exit recess 111 via second channel 113.Note that a contact area between fluid 3 and substrate 4, particularlythe solid-liquid-gas boundary, is completely controlled during the wholeprocess of draining fluid 3. The solid-liquid-gas boundary may firstlyemerge at the center of substrate 4 as a circle. The solid-liquid-gasboundary, while maintaining its circular shape, may gradually enlargeand move from the center of substrate 4 toward the peripheral ofsubstrate 4, and finally disappear at the peripheral of substrate 4. Theenlarging and moving of the solid-liquid-gas boundary would not leaveresidue of fluid 3 at the surface of substrate 4 except for theperipheral of substrate 4, if any. Namely, it is ensured that theresidue of fluid 3 would not appear on substrate 4 except for theperipheral of substrate 4. Various chemical and physical reactionsbetween fluid 3 and the lower surface of substrate 4 may cause differentresults depending on how fluid 3 contacts the lower surface of substrate4. Therefore, it is apparent that a desired processing quality andresult may be achieved through a careful design and manufacturing ofrecess 111, particularly manifested in detailed calculation of a profileand/or slope of the bottom surface of recess 111 in various embodiments.

In the immediate embodiment, fluid 3 may enter recess 111 via firstchannel 112, flow from the center of substrate 4toward the peripheral ofsubstrate 4, and then exit recess 111 via second channel 113 located atthe peripheral of the bottom surface of recess 111. Accordingly, whenfluid 3 is being drained out of recess 111, the solid-liquid-gasboundary between fluid 3 and substrate 4 may emerge at the center ofsubstrate 4 and gradually move toward the peripheral of substrate 4, andfinally disappear at the peripheral of substrate 4.

FIG. 10 illustrates structural features of recess 111 of a semiconductorprocessing apparatus according to another embodiment of the presentdisclosure. As shown in FIG. 10, the bottom surface of recess 111 mayinclude at least a location 1111 that is located at the center of thebottom surface of recess 111. The bottom surface may have a profile of acurve that ascends, against the direction of gravity, from location 1111toward peripheral 1112 of the bottom surface with a decreasing slope.Recess 111 may have a circular projection shape. A spacing betweenrecess 111 and substrate 4 may be smaller at peripheral 1112 of recess111, and yet the spacing becomes larger at center 1111 of recess 111. Asshown in FIG. 10, the spacing between recess 111 and substrate 4 issmaller at X than that at Y. Fluid 3 may enter recess 111 via firstchannel 112, which has a lower opening at the connection to recess 10.Initially, fluid 3 is located at center 1111 of recess 111. As a volumeof fluid 3 entering recess 111 increases, a level of fluid 3 maygradually move higher (i.e., in a direction against the direction ofgravity) and reach peripheral 1112 of the bottom surface, and eventuallyexit recess 111 via second channel 113 that connects to recess 111 atperipheral 1112 of recess 111. During the process, fluid 3 may initiallyhave a contact area only at a central location of the lower surface ofsubstrate 4, which corresponds to center 1111 of the bottom surface ofrecess 111. As the volume of fluid 3 entering recess 111 increases, thecontact area may enlarge toward a peripheral of substrate 4. When thespacing between substrate 4 and body portion 1 has been filledcompletely by fluid 3, fluid 3 may completely cover the lower surface ofsubstrate 4. Since this moment, new fluid 3 may continue entering recess111 via first channel 112, whereas fluid 3 that has contacted the lowersurface of substrate 4 may exit recess 111 via second channel 113. Fluid3 may continually flow over the lower surface of substrate 4 and causevarious chemical and physical reactions at the lower surface ofsubstrate 4. A particular way fluid 3 contacts the lower surface ofsubstrate 4, such as an incident angle and a flowing speed thereof, maydirectly affect a reaction speed and result of the chemical and physicalreactions. The structure of recess 111 as shown in FIG. 10 may provide adifferent diameter at each different height of fluid 3. For example,compared with location X, location Y of FIG. 10 has a smaller diameterwith respect to the center of recess 111, but has a larger spacing fromsubstrate 4. As fluid 3 drains toward the center of recess 111 due togravity, a flowing area of fluid 3 at a specific height of recess 111equals to a circumference created by the radius of recess 111 at thespecific height times the spacing between recess 111 and substrate 4 atthe specific height. As long as the spacing increases at a same rate asthe circumference decreases, the flowing area at different heights wouldremain constant. When the flowing area of fluid 3 at different heightsremains constant, the flowing speed of fluid 3 at different locations ofrecess 111 would remain constant at all time. It follows that fluid 3would process various locations of substrate 4 to a constant extent. Dueto the specially designed structure of recess 111, each location ofsubstrate 4 may be processed substantially equally by fluid 3. Accordingto calculations, the curve in FIG. 10 may be described by a functiony=−C/x, wherein C is a constant of a value greater than 0, an origin ofthe function coincides with the center of substrate 4, and a positivedirection of variable x extends from the center of substrate 4 towardsthe peripheral of substrate 4. A larger value of constant C mayrepresent a flowing speed of fluid 3 of a smaller constant value acrossvarious locations of recess 111, assuming a constant amount of fluid 3entering and exiting recess 111. On the other hand, a smaller value ofconstant C may represent a flowing speed of fluid 3 of a larger constantvalue across various locations of recess 111, also assuming a constantamount of fluid 3 entering and exiting recess 111. In anotherembodiment, with the same definition of the origin of the function andthe positive direction of variable x as defined above, the curve in FIG.10 may be described by a function y=A·In(x)+C, wherein each of A and Cis a constant. By adjusting the values of A and C, fluid 3 may becontrolled to have different values of flowing speed at differentlocations of recess 111, resulting in a varying flowing speed as fluid 3flows at various locations of recess 111. For example, in a firstscenario, values of A and C may be adjusted such that fluid 3 may havean increasing flowing speed as fluid 3 flows from the center to theperipheral of the lower surface of substrate 4. In a second scenario,values of A and C may be adjusted such that fluid 3 may have adecreasing flowing speed as fluid 3 flows from the center to theperipheral of the lower surface of substrate 4.

FIG. 11 is a sectional view of a semiconductor processing apparatusaccording to another embodiment of the present disclosure. FIG. 11Aillustrates a zoom-in view of circle I of FIG. 11, whereas FIG. 11B is asectional view along sectional line A-A of FIG. 11. FIG. 11C illustratesa zoom-in view of circle I of FIG. 11B according to an embodiment of thepresent disclosure, and FIG. 11D illustrates a zoom-in view of circle Iof FIG. 11B according to another embodiment of the present disclosure.As shown in FIG. 11, body portion 1 may include a plurality ofsemiconductor processing units 11 that are mutually independent. Each ofthe plurality of semiconductor processing units 11 may be capable oftreating or processing a respective region on a same side of a substrate4. As shown in FIGS. 11A and 11B, five semiconductor processing units 11that are mutually independent may be disposed on body portion 1 of thesemiconductor processing apparatus. Body portion 1 also may also have afirst groove 12 that is disposed on an outer side of all of theplurality of semiconductor processing units 11. First groove 12 may becapable of collecting fluid 3 that may overflow from the plurality ofsemiconductor processing units 11. Body portion 1 may further include athird channel 13 that is connected to first groove 12. Third channel 13may be capable of sending or otherwise drain the fluid 3 collected inthe first groove 12 to the outside. Each of the plurality ofsemiconductor processing units 11 may be capable of independentlytreating a respective region of substrate 4. Namely, during thetreatment, fluid 3 in a semiconductor processing unit 11 would notaffect other regions of substrate 4. As shown in FIG. 11C, for any oneof the plurality of semiconductor processing units 11, location 1111 maybe located at the center of the bottom surface of recess 111 of thatparticular semiconductor processing unit 11. The bottom surface ofrecess 111 may be a slope that ascends from location 1111 towardperipheral 1112 of the bottom surface against the direction of gravity.Fluid 3 may enter or exit recess 111 via first channel 112, and fluid 3may also enter or exit recess 111 via second channel 113. In analternative embodiment, as shown in FIG. 11 D, for any one of theplurality of semiconductor processing units 11, the bottom surface ofrecess 111 may be a slope that descends from location 1111 towardperipheral 1112 of the bottom surface following the direction ofgravity. Similarly, fluid 3 may enter or exit recess 111 via firstchannel 112, and fluid 3 may also enter or exit recess 111 via secondchannel 113.

The semiconductor processing apparatuses, as disclosed above, may becapable of processing substrates for different purposes, such ascleaning, passivation and inspection of a semiconductor surface.Apparently, the substrates may include other objects of thin slices,such a plate of glass, a plate of plastic or other kinds of plates.

According to another aspect of the present disclosure, a semiconductorprocessing method is disclosed. The semiconductor processing method maybe capable of cleaning a surface of a semiconductor substrate, and/orremoving an oxidation layer at the surface of the semiconductorsubstrate. The semiconductor substrate may be a crystal wafer or asilicon wafer or other semiconductor devices. The semiconductorprocessing method may include the following steps:

(1) Place a substrate 4 that is to be processed on top of a recess 111of a body portion 1. Body portion 1 may have a first channel 112 and asecond channel 113, each of which may connect to recess 111. An openingof first channel 112 where first channel 112 connects to recess 111 islocated at a different height from a height of an opening of secondchannel 113 where second channel 113 connects to recess 111. In someembodiments, recess 111 may have at least one location 1111 located at acenter of a bottom surface of recess 111. The bottom surface may descendfrom location 1111 toward a peripheral 1112 of the bottom surfacefollowing a direction of gravity. The opening of the first channel 112may be higher than the opening of the second channel 113.

(2) Send a fluid 3 to recess 111 via at least one of first channel 112and second channel 113. Fluid 3 may fill up a space between a lowersurface of substrate 4 and body portion 1. Moreover, fluid 3 may contactthe lower surface of substrate 4. In some embodiments, fluid 3 may beone or more of a hydrofluoric acid solution, a nitric acid solution, ahydrogen peroxide and any other kind of fluid that is capable ofcleaning the lower surface of substrate 4.

(3) Drain fluid 3 inside recess 111 via one of first channel 112 andsecond channel 113 that has an opening that is located at a lowerlocation. Meanwhile, send fluid 3 to recess 111 via the other one offirst channel 112 and second channel 113, which has an opening that islocated at a higher location. During this process, maintain fluid 3 in astate that contacts the lower surface of substrate 4 so that fluid 3 mayprocess the lower surface of substrate 4. In some embodiments, fluid 3may include a hydrofluoric acid solution and/or a nitric acid solutionsuch that an oxidation layer at the lower surface of substrate 4 may beremoved thereby, and the lower surface of substrate 4 may becomehydrophobic.

(4) Stop sending fluid 3 to recess 111 via the one of first channel 112and second channel 113 that has an opening located at a higher location.

(5) Drain fluid 3 inside recess 111 out of recess 111 via one of firstchannel 112 and second channel 113 that has an opening located at alower location. A solid-liquid-gas boundary may be formed between fluid3 and the lower surface of substrate 4. Control a moving speed and amoving direction of the solid-liquid-gas boundary by controlling aflowing speed of fluid 3 as fluid 3 exits recess 111, which subsequentlycontrols an amount and a physical distribution of a residue of fluid 3at the lower surface of substrate 4.

In an event that the moving speed of the solid-liquid-gas boundarysatisfies a first predetermined condition, fluid 3 may leavesubstantially no residue on the lower surface of substrate 4 as thesolid-liquid-gas boundary moves across the lower surface of substrate 4.Specifically, the lower surface of substrate 4 may be hydrophobic, andthe solid-liquid-gas boundary between fluid 3 and the lower surface ofsubstrate 4 may move either from a center of substrate 4 to a peripheralof substrate 4, or from the peripheral of substrate 4 to the center ofsubstrate 4. Therefore, as the solid-liquid-gas boundary moves acrossthe lower surface of substrate 4, fluid 3 may leave residue only at alocation where fluid 3 is finally separated from substrate 4, and wouldnot leave residue at any other location of substrate 4. That is, in anevent that the solid-liquid-gas boundary moves from the peripheral ofsubstrate 4 to the center of substrate 4, the residue of fluid 3, ifany, could only appear at the center of substrate 4. Similarly, in anevent that the solid-liquid-gas boundary moves from the center ofsubstrate 4 to the peripheral of substrate 4, the residue of fluid 3, ifany, could only appear at the peripheral of substrate 4. In either case,residue of fluid 3 would not stay at other locations of substrate 4,thereby ensuring a quality of substrate 4 as the residue may containcontaminants from the cleaning process.

In an event that the moving speed of the solid-liquid-gas boundarysatisfies a second predetermined condition, fluid 3 may form a thin filmof a predetermined thickness on the lower surface of substrate 4.Specifically, when fluid 3 exits recess 111 at a higher existing speed,the solid-liquid-gas boundary may move faster as fluid 3 and substrate 4separate from one another. Fluid 3 may thus leave on the lower surfaceof substrate 4 a layer of residue having the predetermined thickness.

In one aspect of the method according to the present disclosure, asituation of contact between fluid 3 and substrate 4 may be wellcontrolled, thereby controlling a situation of reaction or cleaning ofsubstrate 4 by fluid 3. In another aspect of the method according to thepresent disclosure, an exiting speed of fluid 3 leaving recess 111 maybe well controlled, thereby controlling an amount and a distribution ofa residue of fluid 3 left on the lower surface of substrate 4.Specifically, when operating a cleaning process to substrate 4, theresidue of fluid 3 may be controlled such that substantially no residueis left on the lower surface of substrate 4 (except for possibly at thecenter or the peripheral of substrate 4). Alternatively, it may becontrolled such that fluid 3 may form a thin film of a predeterminedthickness, and the thin film may be used to protect the lower surface ofsubstrate 4. For example, the thin film may prevent the lower surface ofsubstrate 4 from contacting the air and having a reaction with the air.

According to another aspect of the present disclosure, a testing methodmay be included to test a cleanness of a substrate after the substrateis cleaned using the method disclosed above, as follows:

(1) Place a substrate 4 on top of recess 111 of body portion 1 afteradding 20 nanograms (ng) of ionic contaminant of a certain metal.Dispose cover portion 2 on top recess 111 of body portion 1.

(2) Send fluid 3 of a volume of 1.2V into recess 111 via one of firstchannel 112 and second channel 113 that has an opening located at ahigher location. Fluid 3 may be a hydrofluoric acid solution, a nitricacid solution, a hydrogen peroxide or a combination of thereof. Unit “V”above represents a volume of a space between substrate 4 and recess 111.An extra 0.2V of fluid 3 is sent into recess 111 to guarantee fluid 3may be able to sufficiently clean a lower surface of substrate 4. Fluid3 of volume 1V that remains in recess 111 may be collected and used totest a situation of remnant contaminants on the lower surface ofsubstrate 4.

(3) Send in ultrapure water of a volume of 20V into recess 111, via oneof first channel 112 and second channel 113 that has an opening locatedat the higher location, to wash substrate 4. Collect fluid 3 and theultrapure water via one of first channel 112 and second channel 113 thathas an opening located at a lower location.

(4) Perform inductively coupled plasma mass spectrometry (ICP-MS) on thefluid 3 and the ultrapure water collected above. Specifically, calculatea result using a standard addition method and add 20 ng of ioniccontaminant of certain metal A. For example, ICP-MS may measure anamount of 18 ng of the ionic contaminant. Considering that the extra0.2V of fluid 3 may also contain some ionic contaminant, a collectionrate of the ionic contaminant is thus over 90%. Compared with existingsubstrate cleaning/washing methods such as wet cleaning techniques thatinvolve chemical immersion and/or spraying, the cleaning methodaccording to the present disclosure achieves prominent cleaning resultsusing an extremely low volume of fluid 3 and ultrapure water.Semiconductor industry consumes large amounts of various fluids andwater resources that very much surpass imagination of the generalpublic, causing serious environmental impacts and aggravating scarcenessof water resources. The semiconductor cleaning method according to thepresent application may save a large quantity of fluid 3 and ultrapurewater, thereby reducing the impact fluid 3 may bring to the environment.

According to another aspect of the present disclosure, a semiconductorpassivation method is proposed. The semiconductor applicable to themethod may include crystal wafers, silicon wafers or other semiconductorsubstrates. The method firstly removes an oxidation layer at a surfaceof a substrate, and secondly performs passivation to the surface. Themethod may include the following steps:

(1) Place a substrate 4 that is to be processed on top of a recess 111of a body portion 1. Dispose cover portion 2 on top recess 111 of bodyportion 1. In some embodiments, recess 111 may have at least onelocation 1111, and a bottom surface of recess 111 may descend fromlocation 1111 toward a peripheral 1112 of the bottom surface following adirection of gravity. In some alternative embodiments, the bottomsurface of recess 111 may ascend from location 1111 toward theperipheral 1112 of the bottom surface against a direction of gravity.Body portion 1 may have a first channel 112 connecting to recess 111 atlocation 1111. Body portion 1 may also have a second channel 113connecting to recess 111 at peripheral 1112 of the bottom surface. Oneof first channel 112 and second channel 113 may be used to send a fluidinto recess 111, whereas the other one of first channel 112 and secondchannel 113 may be used to drain the fluid out of recess 111. Each offirst channel 112 and second channel 113 may connect to recess 111 at anopening, and the opening of first channel 112 may be located at adifferent height from the opening of second channel 113. In a preferredembodiment, location 1111 may be located at a center of the bottomsurface of recess 111. The bottom surface of recess 111 may ascend fromlocation 1111 toward the peripheral 1112 of the bottom surface against adirection of gravity, and may have a cross sectional profile that may bedescribed by a curve represented by a function of y=−C/x or y=A·In(x)+C,wherein A and C are constants. The opening of the first channel 112 maybe lower than the opening of the second channel 113.

(2) Send the fluid to recess 111 via at least one of first channel 112and second channel 113. The fluid may be capable of removing anoxidation layer at the lower surface of substrate 4. The fluid may fillup a spacing fill up a space between a lower surface of substrate 4 andbody portion 1. Moreover, the fluid may contact the lower surface ofsubstrate 4. The fluid may then be drained out of recess 111 via one offirst channel 112 and second channel 113, of which the opening is at alower location. Generally, a hydrofluoric acid solution may be used asthe fluid to remove the oxidation layer. Apparently, other types offluid capable of remove an oxidation layer may be employed. After theoxidation layer is removed from the lower surface of substrate 4, thelower surface of substrate 4 may become hydrophobic. After the fluid hasworked to remove the oxidation layer to certain degree, the fluid may bestopped from being sent into recess 111 any further.

(3) In an event that a density of the fluid inside recess 111 reaches athird predetermined condition, ultrapure water may be sent into recess111 via one first channel 112 and second channel 113 that has an openingat a higher location. The ultrapure water may wash the lower surface ofsubstrate 4 and remove residue of the fluid left thereon. In an eventthat the density of the fluid inside recess 111 never reaches the thirdpredetermined condition, one may proceed to the next step. This isbecause if the density of the fluid is lower than the thirdpredetermined condition, it is not necessary to wash the lower surfaceof substrate 4 and remove residue of the fluid left thereon.

(4) Send passivation substance to recess 111 via either one of firstchannel 112 and second channel 113. The passivation substance may form apassivation layer on the lower surface of substrate 4. Meanwhile, drainor remove the passivation substance from recess 111 via either one offirst channel 112 and second channel 113.

(5) When a passivation requirement is met after a certain amount ofpassivation substance has been sent to recess 111, stop sending morepassivation to recess 111. Whether or not the passivation requirement ismet may be judged by the amount of passivation substance that has beensent to recess 111, or by a period of time over which the passivationsubstance has been sent to recess 111. Apparently, substantially nofurther passivation may be formed on the lower surface of substrate 4after a certain degree of passivation has been achieved thereon.

The passivation substance may be gas (such as ozone) or liquid.Obviously, the present method may be applicable to other passivationsubstances that are being used in existing passivation techniques. Thepresent method requires the passivation substance to be sent into recess111 only, which would require a very small amount of the passivationsubstance as compared to various existing techniques, and would resultin a more complete and more even passivation result. A testing methodmay be included to test the passivation after a passivation layer isformed using the method disclosed above, as follows:

(1) Place a substrate 4 that is to be processed on top of a recess 111of a body portion 1. Dispose cover portion 2 on top recess 111 of bodyportion 1.

(2) Slowly send 150 milliliter (mL) of hydrofluoric acid solution of 10%mass percentage to recess 111 via either one of first channel 112 andsecond channel 113, for removing any oxidation layer that may haveformed on a surface of substrate 4. Drain the hydrofluoric acid solutioninside recess 111 via one of first channel 112 and second channel 113that has an opening that is located at a lower location.

(3) Slowly send 250 mL of ultrapure water into recess 111 via one offirst channel 112 and second channel 113 that has an opening located ata higher location, for washing away residue of the hydrofluoric acidsolution left in recess 111. The ultrapure water may be drained via oneof first channel 112 and second channel 113 that has an opening locatedat a lower location. Since the surface of substrate 4 becomeshydrophobic after being treated by the hydrofluoric acid solution, theultrapure water would not leave residue on the surface of substrate 4except for a peripheral or a center of substrate 4. Thus, most area ofthe surface of substrate 4 may be ensured to have a good quality.Moreover, a step for drying water residue of the surface of substrate 4would not be necessary.

(4) Send ozone gas into recess 111 via either one of first channel 112and second channel 113, for forming a passivation layer on the surfaceof substrate 4. Shut off the ozone gas after sending the ozone gas intorecess 111 for 10 minutes.

(5) Remove cover portion 2 to get access to recess 111 and removesubstrate 4. Inspect the surface of substrate 4 using a film thicknessgauge and measure that an average thickness of an oxidation layer on thesurface of substrate 4.

For example, the thickness may be 14 angstroms (A), with a standarddeviation of 5%. Accordingly, the passivation method according to thepresent disclosure may obtain an oxidation layer of more even thickness,reducing a probability of having varying thickness in different regionsof the surface of substrate 4.

According to another aspect of the present disclosure, a semiconductorsurface inspection method is proposed for inspecting a contaminantdistribution in different regions of a semiconductor surface. The methodmay include the following steps:

(1) Place a substrate 4 that is to be inspected on top of a body portion1 having a plurality of semiconductor processing units 11, with a lowersurface of substrate 4 abutting the plurality of semiconductorprocessing units 11. The plurality of semiconductor processing units 11may be arranged according to different regions of substrate 4 that areto be inspected. A quantity of semiconductor processing units of theplurality of semiconductor processing units 11 may be determined basedon an inspection requirement. For example, the more regions of substrate4 are to be inspected, a larger quantity of semiconductor processingunits 11 may be disposed on body portion 1. The higher the inspectionaccuracy is required, the higher density at which semiconductorprocessing units 11 may be disposed on body portion 1 is needed. In anembodiment, a bottom surface of a recess 111 of each of the plurality ofsemiconductor processing units 11 may have a location 1111 located at acenter of the bottom surface of recess 111. The bottom surface may be aslope ascending from location 1111 toward a peripheral 1112 of thebottom surface of recess 111 against a direction of gravity. For each ofthe plurality of semiconductor processing units 11, body portion 1 mayhave a first channel 112 connecting to recess 111 at an opening that isat a lower location. Body portion 1 may also have a second channel 113connecting to recess 111 at an opening that is at a higher location.Each of first channel 112 and second channel 113 may be used to send afluid 3 into recess 111, to drain fluid 3 out of recess 111, or to keepa balance of pressure. In an alternative embodiment, the bottom surfacemay be a slope descending from location 1111 toward peripheral 1112 ofthe bottom surface of recess 111 following a direction of gravity. Firstchannel 112 may thus have the opening at a higher location while secondchannel 113 may have the opening at a lower location. That is, theopening of the first channel 112 and the opening of the second channel113 are located at different heights of body portion 1.

(2) Send fluid 3 into the recess 111 of at least one of the plurality ofsemiconductor processing units 11 via either of first channel 112 andsecond channel 113 corresponding to the at least one of the plurality ofsemiconductor processing units 11. Fluid 3 may contact a portion of thelower surface of substrate 4 and take away contaminant thereof. Anappropriate kind of fluid 3 may be chosen depending on the kind ofcontaminant to be inspected. In general, fluid 3 may include a solutionsuch as a hydrofluoric acid solution, a nitric acid solution and/or ahydrogen peroxide solution.

(3) Remove fluid 3 from the recess 111 via either of the first channel112 and second channel 113. For an embodiment that has a bottom surfaceof recess 111 that includes a slope ascending from location 1111 towardperipheral 1112 of the bottom surface against the direction of gravity,fluid 3 may enter recess 111 via first channel 112. As fluid 3 continuesentering recess 111, fluid 3 may contact the lower surface of substrate4 and remove or otherwise dissolve substances from the lower surface ofsubstrate 4. As fluid 3 flows inside recess 111, the dissolvedsubstances may move from a center of substrate 4 toward a peripheral ofsubstrate 4. Fluid 3 may subsequently be drained out of recess 111 viafirst channel 112, and the substances removed from the lower surface ofsubstrate 4 may also be sent out of recess 111 along with fluid 3,subsequently collected and inspected. Since fluid 3 is drained out offirst channel 112, which is located at a bottom location of recess 111,fluid 3 may thus flow with a higher stability when exiting recess 111.Alternatively, fluid 3 may exit recess 111 via second channel 113 alongwith the substances removed from the lower surface of substrate 4, whichmay then be collected and inspected. Draining fluid 3 via second channel113 may result in a more stable amount of the substances removed fromthe lower surface of substrate 4 in the fluid 3 exiting recess 111. Thisis because as fluid 3 continues entering recess 111 via first channel112, fluid 3 may gradually fill up recess 111, pushing most of thesubstances removed from the lower surface of substrate 4 towardperipheral 1112 of the bottom surface of recess 111. The more stableamount of the substances in the fluid 3 exiting recess 111 may beadvantageous to inspection of the substances by an instrument.

(4) For an embodiment that has a bottom surface of recess 111 thatincludes a slope descending from location 1111 toward peripheral 1112 ofthe bottom surface following the direction of gravity, fluid 3 may enterrecess 111 via second channel 113. As fluid 3 continues entering recess111, fluid 3 may contact the lower surface of substrate 4 and remove ordissolve substances from the lower surface of substrate 4. As fluid 3flows inside recess 111, the dissolved substances may move from theperipheral of substrate 4 toward the center of substrate 4. Fluid 3 maysubsequently be drained out of recess 111 via first channel 112, and thesubstances removed from the lower surface of substrate 4 may also besent out of recess 111 along with fluid 3, and subsequently collectedand inspected. Draining fluid 3 via first channel 112 may result in amore stable amount of the substances removed from the lower surface ofsubstrate 4 in the fluid 3 exiting recess 111. This is because as fluid3 continues entering recess 111 via second channel 113, fluid 3 maygradually fill up recess 111, pushing most of the substances removedfrom the lower surface of substrate 4 toward center 1111 of the bottomsurface of recess 111. The more stable amount of the substances in thefluid 3 exiting recess 111 may be advantageous to inspection of thesubstances by an instrument. Alternatively, fluid 3 may exit recess 111via second channel 113 along with the substances removed from the lowersurface of substrate 4, which may then be collected and inspected. Sincefluid 3 is drained out of second channel 113, which is located at abottom location of recess 111, fluid 3 may thus flow with a higherstability when exiting recess 111.

(5) Collect fluid 3 as drained from each of the plurality ofsemiconductor processing units 11. Inspect the collected fluid 3respectively for the substances removed by fluid 3, thereby obtaining adistribution of contaminants in different regions of substrate 4.

The semiconductor surface inspection method described above, as appliedto substrate 4, may inspect contaminants in different regions ofsubstrate 4. Each of the plurality of semiconductor processing units 11may be able to process a respectively one region of substrate 4independently. During the process, any of the plurality of semiconductorprocessing units 11 would not affect any other of the plurality ofsemiconductor processing units 11. Moreover, the fluid used by asemiconductor processing unit 11 would only contact a respectivecorresponding area of substrate 4, and would not flow to other areasthat do not need inspection. This would prevent the fluid from pollutingother unrelated areas. Based on inspection results of the plurality ofsemiconductor processing units 11, a distribution of contaminants indifferent regions of substrate 4 may be obtained. With a large number ofsemiconductor processing units 11, each of the semiconductor processingunits 11 may be responsible for inspecting only a small area, therebyyielding a more ideal and more truthful distribution of contaminantsacross the surface of substrate 4.

The present disclosure has been described in sufficient details with acertain degree of particularity. It is understood to those skilled inthe art that the present disclosure of embodiments has been made by wayof examples only and that numerous changes in the arrangement andcombination of parts may be resorted without departing from the spiritand scope of the present disclosure as claimed. Accordingly, the scopeof the present disclosure is defined by the appended claims rather thanthe foregoing description of embodiments.

1.-14. (canceled)
 15. A semiconductor processing method, comprising: placing a substrate on top of a recess of a body portion with a lower surface of the substrate facing downward for processing, wherein the body portion has a first channel and a second channel each connecting to the recess at a respective opening at a respectively different height; sending a fluid to the recess via at least one of the first channel and the second channel such that the fluid fills up a space between the lower surface of the substrate and the recess and contacts the lower surface of the substrate; and draining the fluid inside the recess via one of the first channel and the second channel that has the respective opening located at a lower location.
 16. The semiconductor processing method of claim 15, wherein the draining of the fluid inside the recess comprises controlling a moving speed and a moving direction of a solid-liquid-gas boundary formed between the fluid and the lower surface of the substrate, thereby controlling an amount and a physical distribution of a residue of the fluid at the lower surface of the substrate.
 17. The semiconductor processing method of claim 16, wherein, when the moving speed of the solid-liquid-gas boundary satisfies a first predetermined condition, the fluid leaves substantially no residue on the lower surface of the substrate as the solid-liquid-gas boundary moves across the lower surface of the substrate.
 18. The semiconductor processing method of claim 16, wherein, when the moving speed of the solid-liquid-gas boundary satisfies a second predetermined condition, the fluid forms a thin film of a predetermined thickness on the lower surface of the substrate as the solid-liquid-gas boundary moves across the lower surface of the substrate.
 19. The semiconductor processing method of claim 15, wherein a bottom surface of the recess descends from a center of the bottom surface toward a peripheral of the bottom surface following a direction of gravity, wherein the first channel has the respective opening at a higher location, and wherein the second channel has the respective opening at a lower location.
 20. The semiconductor processing method of claim 19, wherein, during the draining of the fluid inside the recess, a solid-liquid-gas boundary formed between the fluid and the lower surface of the substrate moves from the center of the bottom surface toward the peripheral of the bottom surface.
 21. The semiconductor processing method of claim 15, wherein a bottom surface of the recess ascends from a center of the bottom surface toward a peripheral of the bottom surface against a direction of gravity, wherein the first channel has the respective opening at a lower location, and wherein the second channel has the respective opening at a higher location.
 22. The semiconductor processing method of claim 21, wherein, during the draining of the fluid inside the recess, a solid-liquid-gas boundary formed between the fluid and the lower surface of the substrate moves from the peripheral of the bottom surface toward the center of the bottom surface.
 23. A semiconductor surface inspection method, comprising: placing a substrate on top of a body portion such that each of a plurality of semiconductor processing units abuts a lower surface of the substrate; sending a fluid to at least one unit of the plurality of semiconductor processing units via either one of a first channel and a second channel of the at least one unit such that the fluid contacts the lower surface of the substrate and removes or dissolves a contaminant at the lower surface of the substrate; draining the fluid via either one of the first channel and the second channel; and respectively collecting and inspecting the fluid drained from the at least one unit to obtain a distribution of the contaminant in different regions of the substrate.
 24. The semiconductor surface inspection method of claim 23, wherein a bottom surface of a recess of each of the plurality of semiconductor processing units ascends from a center of the bottom surface toward a peripheral of the bottom surface against a direction of gravity, wherein the first channel has a respective opening at a lower location, and wherein the second channel has a respective opening at a higher location.
 25. The semiconductor surface inspection method of claim 24, wherein the draining of the fluid comprises draining the fluid via the first channel, and wherein the contaminant removed or dissolved in the fluid moves from the center to the peripheral as the fluid flows in the recess.
 26. The semiconductor surface inspection method of claim 25, wherein the draining of the fluid comprises draining the fluid via the first channel, and wherein the contaminant removed or dissolved in the fluid is drained out of the recess along with the fluid and subsequently collected for inspection.
 27. The semiconductor surface inspection method of claim 25, wherein the draining of the fluid comprises draining the fluid via the second channel, and wherein the contaminant as removed or dissolved in the fluid is drained out of the recess along with the fluid and subsequently collected for inspection.
 28. The semiconductor surface inspection method of claim 23, wherein a bottom surface of a recess of each of the plurality of semiconductor processing units descends from a center of the bottom surface toward a peripheral of the bottom surface following a direction of gravity, wherein the first channel has a respective opening at a higher location, and wherein the second channel has a respective opening at a lower location.
 29. The semiconductor surface inspection method of claim 28, wherein the draining of the fluid comprises draining the fluid via the second channel, and wherein the contaminant as removed or dissolved in the fluid moves from the peripheral to the center as the fluid flows in the recess.
 30. The semiconductor surface inspection method of claim 29, wherein the draining of the fluid comprises draining the fluid via the first channel, and wherein the contaminant as removed or dissolved in the fluid is drained out of the recess along with the fluid and subsequently collected for inspection.
 31. The semiconductor surface inspection method of claim 29, wherein the draining of the fluid comprises draining the fluid via the second channel, and wherein the contaminant as removed or dissolved in the fluid is drained out of the recess along with the fluid and subsequently collected for inspection. 